Retracted: Prediction and optimization of volumetric power draw in an aerated and stirred vessel used in wastewater biological plant: a mathematical model developed by using central composite rotatable design analysis (CCRD)

In this study, the volumetric power draw P/V was determined as a factor in designing and identifying the optimal condition a successful aeration for stirred wastewater biological treatment vessels. The study was performed to characterize the volumetric power draw in the aerated stirred vessels by optimizing the operation variables. The concerning factors were improved by conjugating stirring and aeration with efficient and economic volumetric power draw condition. The drawn volumetric power was tested and analyzed for three independent parameters; impellers rotation speed (100–200 rpm), turbine blades submergence ratio S/W (0.33–1.67) and wastewater height level ratio H/D (1.37–1.58). A mathematical model was developed in the form of a nonlinear polynomial mathematical model to predict the P/V. The optimal values of the P/V and of relevant parameters were computed through the application of the Box–Wilson technique by application of the central composite rotatable design (CCRD) model. The volumetric power draw P/V and the relevant independent parameters are presented in optimal conditions surface plots that obtained from the nonlinear mathematical model. Optimum analysis result for the independent parameters showed low levels of impellers rotation speed and turbine submergence ratio draw lower P/V while wastewater height did not have a clear effect on P/V.